New regulatory requirements emphasize the need to warn employees of the effects of hazardous chemicals. The regulations require that virtually all chemical containers and/or locations where they are being used be provided with visual warnings that clearly identify the chemical and indicate the potential hazards associated with its use. Relevant information relates to health, flammability and reactivity hazards associated with the chemical and an index for assessing the degree of danger for each hazard. The warning on a label should be clearly visible, legible and capable of rapid assessment by the user. The label should be resistant to the environment and to tampering.
The National Fire Protection Agency (NFPA) diamond is a standardized symbol which is widely used to indicate hazards associated with a chemical. The symbol is a vehicle for presenting information on health, flammability, reactivity and special hazards and the degree of the hazard on a scale of 0-4. The diamond shaped symbol has four quadrants, each of which relates to one of the hazards. Three of the quadrants have a different color with an index number superimposed on the color to indicate the degree of hazard. The fourth quadrant is reserved for a symbol to indicate the special hazard. Here to fore the labels have generally been preprinted and applied by the chemical manufacturer at the source of the chemical packaging. Such a system does not lend itself to customization of the label. Such a system provides immediacy, but at some sacrifice of adequacy. It depends on extensive training of individuals on interpretation of the code and suffers from a lack of accuracy, poor understandability, poor response time, lack of effectiveness, and a frequent need to check other sources, such as, a material safety data sheet (MSDS) for additional information.
Labels have been developed for non-hazardous purposes in which some or all of the information on the label is coated with an opaque material to temporarily obscure selected information. The opaque material can be removed by the user to reveal the information which is then interpreted. A problem with removable coatings is that they are not weather resistant and are susceptible to unintentional abrasion which can lead to erroneous or confusing indications and inaccurate interpretation of the indicia or code. In general, this makes them unsuitable for use with warning labels in industry or in severe environmental conditions.
U.S. Pat. No. 5,395,137 (Kim) discloses a color coded label for use in classifying and identifying documents in document handling systems. The label includes a base member in the form of a thin plate and a color code coated on the surface of the base member. The color code is in the form of multiple bands of different colors which are coated with an opaque or semi-transparent material. The opaque coating can be a screen ink which can be partially or completely removed by scraping from one or more bands to expose a pattern of colored bands. The exposed band or pattern of bands corresponds to a predetermined classification or identification. In a preferred embodiment the color code is coated with a transparent plastic coating between the color code and the screen ink coating to protect the color code itself from scraping. There is no disclosure of a transparent plastic cover over the opaque coating to protect the opaque coating prior to use of the label or after the code is set. This color coded system relies on a colored band or combinations of different colored bands to provide specific identification information. There is no disclosure of exposing selected portions of a single colored band to provide quantitative information.
It is an object of this invention to provide a color coded warning label with a removable opaque coating over the color code, in which the removable coating and code are protected before and after the warning code is set.
It is an object of this invention to provide a color code which provides quantitative hazard information and is accurate, easy to use and readily interpreted.